Piriformis syndrome is a clinical condition of non-discogenic sciatica caused by compression of the sciatic nerve by the piriformis muscle and its patho-physiology is not fully understood. It has variable etiologies. The major etiology known includes spasm, edema and inflammation of the piriformis muscle, and sciatic nerve compression by the muscle later on. Patients can be diagnosed immediately with a comprehensive clinical examination and early diagnosis which makes the treatment much easier. A case of piriformis syndrome diagnosed in a patient who presented with radicular low back pain is reported in this study. Differential diagnosis of the piriformis syndrome, a very rare cause of low back pain, should be thoroughly made with the exclusion of other conditions.